A sensor is a device whose purpose is to sense or detect some characteristic of its environs. It does this by converting one form of energy to another. Through the conversion process, the sensor detects events or changes in quantities and provides a corresponding output, generally in the form of analog or digital reading or as an electrical or optical signal. For example, a thermocouple is a sensor that converts temperature to an output voltage. A mercury-in-glass thermometer is also a sensor example which converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated glass tube. To be useful in practical applications a sensor should have three essential characteristics. It must be sensitive to the measured property, insensitive to any other property likely to be encountered in its application, and it must be non-destructive in the sense that it does not influence or alter the measured property.
Numerous types of sensors have been developed over the years for the purpose of detecting and quantifying physical, chemical and biological properties.
Many recent applications require the deployment of groups of sensors of the same type or a mix of sensors of different types to detect or sense specific properties which are not possible through the use of a single sensor. This takes place for example in applications where the detection of specific characteristics must be done over a large geographic area, such an in environmental or agricultural applications. In other applications, the output of a single type of sensors is not sufficient to identify with accuracy the object being detected. In such cases, the output of different types of sensors may be combined using analytical approaches in order to achieve the target objective. Examples of such applications that require the deployment of heterogeneous group of sensors include the investigation of a crime scenes and search and rescue missions in bad climate conditions.
An Integrated Sensors Platform is a structure which combines a group of sensors of similar or dissimilar types, together with the data processing system that collects and analyses the output of the sensors in real time for the purpose of producing accurate and timely detection outcome. The platform will have different form factors and the flow of information among the sensors and with the data processing system can be through direct connectors or over wireless channels.